The American Academy of Pediatrics points out that it doesn’t matter in what order you introduce foods to your baby's diet, as long as you introduce one food at a time. The exceptions to this rule are cow's milk and honey, which you should not give until after your infant is at least 1 year old. As your baby tries new foods, watch for symptoms of allergies, which may vary depending on the type of allergy your baby may have.
Note any changes in the skin, the most common reactions to a food allergy. Skin reactions include hives, eczema, redness and swelling of the face, and itching and swelling of the lips, tongue and mouth.
Observe vomiting, diarrhea or signs that your infant has stomach pain.
Detect changes in the respiratory tract, such as wheezing, couching, shortness of breath, sneezing, and a runny or stuffy nose.
Note if your infant appears lightheaded or even faints.
Observe irritability, vomiting, wheezing, swelling, hives, any other itchy bumps on the skin, or bloody diarrhea immediately after giving your infant cow’s milk. These symptoms signify a rapid-onset reaction to milk, which is not as common as a slower-onset reaction.
Witness irritability, colic, vomiting, gagging, skin rashes, or loose stools that may or may not contain blood, seven to 10 days after giving your infant cow’s milk. Refusing food is another symptom of a slower-onset reaction to cow’s milk.
Notice the signs of anaphylaxis, a potentially life-threatening allergic reaction that usually occurs immediately after contact with the food culprit. These signs include trouble breathing, wheezing, coughing, vomiting, racing heartbeat, and skin redness or swelling. If your infant does not get enough oxygen, the skin may turn blue. Call 911 if you suspect anaphylaxis.